Patients with early onset of type 1 diabetes have significantly higher GG genotype at position 49 of the CTLA4 gene

Type 1 diabetes (T1D) is a complex autoimmune disease. Several genetic loci have been implicated in the susceptibility to this illness. Evaluated was the role of the CTLA4 exon 1 A49G polymorphism and its role as a risk factor for T1D in our population. DNA from 190 patients with T1D and their families and 96 control individuals were genotyped for CTLA4 exon 1 polymorphism and human leukocyte antigen (HLA)–DQB1*0201 and *0302 haplotypes by polymerase chain reaction (PCR) amplification–restriction enzyme analysis and PCR amplification that used sequence-specific primers, respectively. Patients were nonobese and